Manipulation of lipid metabolism in (+)RNA virus replication

所有(+)RNA病毒都会改变细胞质膜，如内质网(ER)，以建立复制隔间(RC)。这些RC被认为形成了一个膜相关复制酶的平台，除了保护病毒RNA免受胞质Rig-I样受体的影响外，后者还触发了先天性免疫信号和RNA降解机制。我们和其他人已经证明，RC形成的病毒机制中的一个关键成分是RC膜脂组成的调节。我们先前发表了至少3个(+)RNA病毒家族(布罗夫病科、短冠病毒科和黄病毒科)具有刺激磷脂酰胆碱(PC)在RCS蓄积的特性。这表明了解病毒对PC合成的调节可能作为RC形成的一种保守机制具有广泛的意义。我们扩展了这一观察，以获得对这一过程的重大机械性洞察。具体目标是：目的1.确定PC合成对病毒复制的贡献。我们假设PC合成的激活有助于病毒RCS的形成，并可能通过改变内质网脂质成分来影响病毒粒子的感染性。目的2.明确丙型肝炎病毒调节PC合成的机制。目的3.明确ASCL酶在丙型肝炎病毒复制中的意义。ASCL定位于RCS，是复制丙型肝炎病毒所必需的。我们假设是一种病毒蛋白招募它们加入RCS，并要求它们为磷脂提供长链脂肪酸，如PI和PC。

All (+) RNA viruses modify cytoplasmic membranes, such as the endoplasmic reticulum (ER) to establish replication compartments (RCs). These RCs are thought to form a platform for membrane- associated replicases, in addition to protecting the viral RNAs from cytosolic RIG-I-like receptors that trigger innate immune signaling and RNA-degradation machinery. We and others have shown that a key component in the viral mechanism of RC formation is the modulation of RC membrane lipid composition. We previously published that at least 3 (+) RNA virus families (Bromoviridae, Picornaviridae, and Flaviviridae) share the property of stimulating phosphatidyl choline (PC) accumulation at RCs. This suggests that understanding viral modulation of PC synthesis may have broad implication as a conserved mechanism in RC formation. We have extended this observation to gain significant mechanistic insight into this process. The specific aims are: Aim 1. Define the contribution of PC synthesis for viral replication. We hypothesize the activation of PC synthesis aids the formation of viral RCs and may also impact virion infectivity via altered ER lipid composition. Aim 2. Define the mechanism by which HCV modulates PC synthesis. Aim 3. Define the significance of the ASCL enzymes in HCV replication. ASCLs localize to RCs and are required for HCV replication. We hypothesize that a viral protein recruits them to RCs and that they are required to provide the long chain fatty acids for phospholipids, such as PI and PC.